Conventional fuel cell systems include: a reformer configured to generate hydrogen gas (fuel gas) from a natural gas or the like; a fuel cell configured to generate power through an electrochemical reaction between the hydrogen gas and oxygen (air) acting as an oxidant (hereinafter, the fuel cell may be referred to as a stack, as necessary); a power conversion circuit configured to convert electrical energy generated by the stack into a voltage/frequency for commercial use (hereinafter, the power conversion circuit may be referred to as an inverter, as necessary); a ventilator configured to ventilate a package; and auxiliary devices (accessories) for allowing the stack and the reformer to operate smoothly. These devices are disposed within the package (see Patent Literature 1, for example).
FIG. 6 is a schematic diagram showing a schematic configuration of a fuel cell apparatus disclosed in Patent Literature 1.
As shown in FIG. 6, the fuel cell apparatus disclosed in Patent Literature 1 includes: a package 101; a fuel reforming device 102; a fuel cell 103; an electric control device 104 including an inverter; accessories 105; and a ventilation fan 106 serving as a ventilator for introducing external air into the package 101.
Within the package 101, the accessories 105 are disposed at the lowermost position. The fuel reforming device 102 and the electric control device 104 are arranged side by side above the accessories 105. The fuel cell 103 is disposed above the electric control device 104. The ventilation fan 106 is disposed, above the fuel reforming device 102, at a side face of the package 101.
The fuel reforming device 102 includes: a reformer configured to generate a hydrogen gas from a reforming reaction between water (steam) and a raw material gas such as a natural gas; and a burner for heating the reformer. The burner is a component which requires maintenance. Therefore, the burner is configured such that the burner is detachable from the reformer. Generally speaking, the burner has a length that is similar to the overall length of the reformer so that the burner can heat a wide area within the reformer, and the burner is detachably configured so that the burner can be inserted into or removed from the fuel reforming device 102 through the top of the reformer.
There is a very strong demand particularly for household fuel cell systems to be compact in size so that they can be installed in various houses having a wide variety of structures. Therefore, in general, in fuel cell systems, space between the components is reduced as much as possible, and thereby the fuel cell systems are configured to be compact in size.    PTL 1: Japanese Laid-Open Patent Application Publication No. 2003-229148